Glossary of terms
Find definitions for Relay-specific terminology and concepts.
Read time 5 minutesLast updated 14 hours ago
accept mode
The accept mode defines how a Relay server handles requests from clients trying to connect. The accept mode is alwaysAUTOACCEPTED message
An ACCEPTED message is a message type in the Relay Message Protocol specification that indicates a confirmation message sent from a Relay server to a requesting client after a successful connection to a target client.allocation
An allocation is a request to reserve space on a Relay server for the host and the number of players the host is expecting to join their game (indicated with themax_players/allocateallocation ID
A unique identifier of a player’s allocation on a Relay server.allocations service
The entry point for interacting with the Relay service. It exposes a public-facing API that allows players to allocate a slot on a Relay server.best available Relay server
A Relay server that best fits the needs of an allocation request.BIND
message
A BINDBINDBIND_RECEIVED
message
A BIND_RECEIVEDBIND_RECEIVEDBINDclient
Check out game client.client timeout
Check out timeout time to live.CLOSE
message
A CLOSECLOSECONNECT_REQUEST
message
A CONNECT_REQUESTCONNECT_REQUESTconnecting player
A connecting player (or joining player) is a player that wants to join a host player for a game session on a Relay server.connection data
An opaque data blob that uniquely represents a player's connection to a Relay server. The primary purpose of connection data is for establishing aRELAYconnection details
The connections details represent a player's connection to a Relay server and include the Relay server IP address, the Relay server port, the secret key, and the player's allocation ID.connection slot
A logical place on a Relay server that a player can connect to.datagram
A basic unit of data within a packet-switched network. A datagram typically consists of a header and payload. For more information, check out RFC 1594.dedicated game server
A game server hosted on a remote machine that multiple players can connect to by using a game client.DGS
Check out dedicated game server.DISCONNECT message
A DISCONNECT message is a message type in the Relay Message Protocol specification that indicates a request to disconnect two connected players.ERROR message
An ERROR message is a message type in the Relay Message Protocol specification that indicates an error that has occurred.friends system
A subsystem of a game that allows players to communicate with one another and to add players as friends.game client
Clients, or game clients, are executable programs that players use to play a game. Clients allow players to connect to other players to participate in a game match in multiplayer games.game match
In the Relay service, a game session is an active match between multiple players connected through a Relay server. One player is the host player to which the other connecting players communicate using the Relay message protocol.game session
Check out game match.HMAC
An HMAC, or hash-based message authentication code, is a message authentication code that uses a cryptographic hash function and keys to authenticate messages.host player
A host player is a player that initiates a game session on a Relay server and generates a join code to share with other players. There is only one host player per game match.idle timeout
An idle timeout disconnects a player from a Relay server when no Relay protocol messages are detected for a specific amount of time. Game clients can prevent an idle timeout by periodically sending aPINGjoin code
A simple, randomly generated code that allows connecting players to join a host player's game.joining player
Check out connecting player.max connections
Check out maximum connections.maxConnections
Check out maximum connections.maximum connections
An integer that indicates the maximum number of peer connections a client allows to communicate with them. This parameter must be less than or equal to 150.multi-tenanted
Multi-tenanted refers to software architecture in which a single instance of a process runs on a server and serves multiple tenants. Relay servers are multi-tenanted.nonce
A nonce, or cryptographic nonce, is an incrementing number that's used in cryptographic communication to ensure earlier messages can't be resent arbitrarily. Each following message must increment the nonce. This way, if a bad actor tries to use a earlier message in a replay attack, the service can reject the message. In the Relay service, you use nonces as part of the HMAC creation process.out-of-band
Out-of-band communication is communication that occurs outside of the game client. Examples of out-of-band communication include third-party chat services and spoken word.PING
message
A PINGPINGplayer
A player is an end-user connected to a game client who wants to play in a game match. In Relay, each game match has a single host player and one or more connecting players.player ID
Check out player identity.player identity
A unique ID identifying a player connected to a Relay server. Because players can only communicate with other players within the same session, player IDs aren't globally unique.Relay IP
The IPv4 IP address of the Relay serverRELAY
message
A RELAYRELAY